EASTAMPTON, N.J. (CBS) – A New Jersey police officer accused of shooting and killing a man on a Maryland highway, has been arrested there.

40-year-old Joseph Walker was off duty when this all happened.

State Police say there was some kind of altercation after the victim, 36-year-old Joseph Harvey, merged onto Interstate-97. Both men then pulled their cars off onto the side of the road.

“People exited their vehicles and the driver of the Honda started approaching Walker, who got out of his minivan and brandished a firearm, and then ended up shooting Harvey, who has been pronounced dead,” Maryland State Police spokeswoman Elena Russo said.

Walker is from Eastampton, Burlington County and is an officer with the Hudson County Prosecutor’s office in North Jersey.

Walker’s wife and three children were inside the vehicle when this happened. He now faces second degree murder and manslaughter charges.